Re: [PATCH] x86 (Linux Tiny): configure out support forsome processors

From: Simon Holm Thøgersen
Date: Sat Feb 09 2008 - 04:59:52 EST



lÃr, 09 02 2008 kl. 10:29 +0100, skrev Michael Opdenacker:
> On 02/09/2008 09:30 AM, Simon Holm ThÃgersen wrote:
> > The build of my currently running kernel for my laptop has
> > $ size -t amd.o cyrix.o centaur.o transmeta.o intel.o nexgen.o umc.o
> > text data bss dec hex filename
> > 2809 316 0 3125 c35 amd.o
> > 2387 856 0 3243 cab cyrix.o
> > 1514 312 0 1826 722 centaur.o
> > 1279 312 0 1591 637 transmeta.o
> > 1783 316 0 2099 833 intel.o
> > 126 312 0 438 1b6 nexgen.o
> > 41 312 0 353 161 umc.o
> > 9939 2736 0 12675 3183 (TOTALS)
> >
> > That is without optimize for size compilation, with that set I get
> > $ size -t amd.o cyrix.o centaur.o transmeta.o intel.o nexgen.o umc.o
> > text data bss dec hex filename
> > 2300 316 0 2616 a38 amd.o
> > 2132 820 0 2952 b88 cyrix.o
> > 1325 312 0 1637 665 centaur.o
> > 1151 312 0 1463 5b7 transmeta.o
> > 1575 316 0 1891 763 intel.o
> > 107 312 0 419 1a3 nexgen.o
> > 41 312 0 353 161 umc.o
> > 8631 2700 0 11331 2c43 (TOTALS)
> >
> > I don't think the code changes in the patch do much with respect to
> > size.
> >
> Thanks for this report. Don't you think it's still useful to save up to
> 12 K of code that you don't use if you just have an Intel processor (for
> example)?

The last remark was only about the code changes in
arch/x86/kernel/cpu/common.c, arch/x86/kernel/process_32.c,
arch/x86/kernel/process_64.c and arch/x86/mm/init_32.c, which my report
didn't reflect upon since I never applied the patch. The ~12kB reduction
no doubt has a good gain/pain ratio.

Out of curiosity, how small a kernel are you targeting this work for? I
guess your other post on 'make allnoconfig + CONFIG_EMBEDDED' has
disabled more stuff than you would use in practice?


Simon

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